DELPHI弹出USB设备
关键代码已经找到了,可我对API不熟悉,高手帮我看看
==================
function CM_Get_DevNode_Status(pulStatus: PULong; pulProblemNumber: PULong;
dnDevInst: DWord; ulFlags: ULong): DWord; stdcall;
external CfgMgr32ModuleName name 'CM_Get_DevNode_Status';

function CM_Request_Device_Eject(dnDevInst: DWord; out pVetoType: TPNPVetoType;
pszVetoName: PChar; ulNameLength: ULong; ulFlags: ULong): DWord; stdcall;
external SetupApiModuleName name 'CM_Request_Device_EjectA';


if (CM_Get_DevNode_Status(@Status, @Problem, DeviceInfoData.DevInst, 0) <> CR_SUCCESS) then
begin
exit;
end;
VetoName[0] := #0;
case CM_Request_Device_Eject(DeviceInfoData.DevInst, VetoType, @VetoName, SizeOf(VetoName), 0) of
CR_SUCCESS:
begin
MessageBox(Handle, PChar(’Eject OK (Veto: ' + VetoName + ')'), 'Vetoed', MB_OK); end;
CR_REMOVE_VETOED:
begin
MessageBox(Handle, PChar('Failed to eject the Device (Veto: ' + VetoName + ')'), 'Vetoed', MB_OK);
end;
else
begin
MessageBox(Handle, PChar('Failed to eject the Device (' + SysErrorMessage(GetLastError) + ')'), 'Failure', MB_OK);
end;
end;
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是不是根据USB名称识别出来,再卸载USB设置的?能不能直接写上某个USB名称,然后实现卸载呢?

[解决办法]
if (CM_Get_DevNode_Status(@Status, @Problem, DeviceInfoData.DevInst, 0) <> CR_SUCCESS) then
begin 如果获取当前设备状态失败则做下面工作
exit; 失败退出
end;
VetoName[0] := #0; 设置设备名称为空，然后根据获取的设备状态进行弹出操作，按照操作返回经过进行分支：
case CM_Request_Device_Eject(DeviceInfoData.DevInst, VetoType, @VetoName, SizeOf(VetoName), 0) of
CR_SUCCESS: 分支1： 操作成功则
begin 显示成功提示
MessageBox(Handle, PChar(’Eject OK (Veto: ' + VetoName + ')'), 'Vetoed', MB_OK); end;
CR_REMOVE_VETOED: 分支2： 惨遭失败
begin 显示失败提示
MessageBox(Handle, PChar('Failed to eject the Device (Veto: ' + VetoName + ')'), 'Vetoed', MB_OK);
end;
else 分支3：所有其它情况均为失败
begin 显示失败消息提示
MessageBox(Handle, PChar('Failed to eject the Device (' + SysErrorMessage(GetLastError) + ')'), 'Failure', MB_OK);
end;
end;